Radiographic And Physiological Findings In Patients With Asbestosis

Our plain-English summary of Radiographic And Physiological Findings In Patients With Asbestosis, by A. Zitting, M.S. Huuskonen, K. Alanko, et al (1978).

The study

• Authors: A. Zitting, M.S. Huuskonen, K. Alanko, T. Mattsson
• Published: Scandinavian Journal Of Work, Environment And Health 4(4):275-283, December (1978)
• Type of article: Journal article
• Our copy: from Johns-Manville's own medical library, J-M no. 002163. The article is still under copyright, so we describe it here rather than post it.

In plain English

This Finnish study re-examined people diagnosed with asbestosis at the Institute of Occupational Health. Of 140 living patients, 133 (113 men, 20 women) attended between November 1976 and March 1977. Asbestos sprayers had been exposed to crocidolite, quarry workers to anthophyllite, and others mainly to chrysotile with smaller amounts of other types. At re-examination, X-rays showed mild lung fibrosis in 65 of 133 patients (49%), moderate in 48 (36%) and advanced in 20 (15%). Opacities were more profuse than at diagnosis, and 37 of 54 patients first graded 0/1 had moved to a higher grade. Pleural thickening appeared in 88 of 133 (66%). Among 130 patients tested, vital capacity was reduced in 83 (64%). More severe fibrosis generally went with larger decreases in breathing volumes. The carbon-monoxide transfer factor was generally impaired only in advanced cases. In mild fibrosis, patients with pleural thickening had significantly lower vital capacity and one-second exhaled volume. The authors concluded that the study supported the assumption that lung fibrosis is accompanied by more functional abnormality than pleural changes. X-rays from diagnosis existed for only 116 patients.

We wrote this plain-English summary from the full article with the help of AI, and a second AI model checked each sentence against the article. It is not the authors' wording; the abstract and the article are their own account.

What the study did and found

• Design: Follow-up re-examination of a series of asbestosis patients. Radiographic and lung function findings were compared, and X-rays from diagnosis were compared with X-rays from re-examination.
• Who was studied: 133 Finnish asbestosis patients (113 males, 20 females) diagnosed at the Institute of Occupational Health, Helsinki, among cases reported to the Occupational Disease Register from 1964 to 1976. They were 133 of 140 living patients and were re-examined between November 1976 and March 1977. Groups: 55 insulators, 32 workers in an asbestos cement product factory, 29 workers in an asbestos quarry, 8 asbestos sprayers and 9 others.
• Exposure: Occupational asbestos exposure, with a mean exposure length of 22.1 years. Asbestos sprayers were exposed to crocidolite and asbestos quarry workers to anthophyllite. Other occupations had mixed exposure, mainly chrysotile with smaller amounts of anthophyllite, crocidolite and amosite.
• Main results:
  • At re-examination, the profusion of small opacities was 0/1 to 1/1 (mild) in 65 of 133 patients (49%), 1/2 to 2/2 (moderate) in 48 of 133 (36%), and 2/3 to 3/4 (advanced) in 20 of 133 (15%).
  • Opacities were mostly of the irregular type: 110 of the 133 patients (83%). The most common type was s, seen in 98 patients (74%).
  • Small opacities were more profuse at re-examination than at diagnosis.
  • Of 54 patients whose fibrosis was graded 0/1 at diagnosis, 37 had moved to a higher grade at follow-up.
  • At re-examination, opacities were found in the lower, middle and upper lung zones of 100%, 94% and 34% of patients, respectively.
  • Pleural thickening was present in 66 of 116 radiographs at diagnosis (57%) and in 88 of 133 at re-examination (66%).
  • Pleural calcifications were recorded in 41% of radiographs at diagnosis and in 59% at re-examination. Insulators had relatively fewer calcifications than subjects in other occupations (p less than 0.01).
  • Among the 130 patients who had lung function tests, vital capacity was normal (80% of predicted or more) in 47 (36%) and decreased (below 80%) in 83 (64%).
  • Among the 130 patients tested, the carbon-monoxide transfer factor was decreased (below 80%) in 46 (35%).
  • As a rule, the more severe the fibrosis, the greater the decrease in vital capacity and FEV1 (forced expiratory volume in one second).
  • The transfer factor was generally impaired only in advanced cases (fibrosis 2/3 or more).
  • Obstruction was rarely observed among the patients (10%).
  • In the group with mild fibrosis, vital capacity and FEV1 were significantly lower in patients with pleural thickening than in those without (p less than 0.01).
  • No association could be shown between pleural calcifications and functional impairment.
  • Vital capacity did not differ significantly by smoking habits. In the mild fibrosis group, smokers showed signs of obstruction more often than nonsmokers (p less than 0.05).
  • The type of asbestos by occupation had no significant effect on the radiographic findings.
• The authors' conclusion: The authors concluded that their study supported the assumption that pulmonary fibrosis is accompanied by a greater degree of functional abnormality than pleural changes.
• Limitations the authors state:
  • Radiographs from the time of diagnosis were available for only 116 of the 133 patients.
  • The diagnostic criteria were not fully certain: a person with occupational asbestos exposure and interstitial lung fibrosis does not necessarily have asbestosis, particularly with slight exposure and fibrosis classified as 0/1.
  • The lack of progression in 17 patients first graded 0/1 may in many cases reflect the short interval between diagnosis and follow-up.
  • The absence of clear progression in pleural thickening may be due to the coarser grading scale: 3 grades for pleural thickening versus 10 for lung opacities.
  • Quarry workers' asbestosis appeared to be certified earlier, probably because they had been checked more carefully through periodic health examinations.

Topics

Medical terms in this study, explained in our Lexicon: Crocidolite, Anthophyllite, Chrysotile, Fibrosis, Pleural Thickening.

Browse return to medical research.